/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#pragma once

#include <android-base/chrono_utils.h>
#include <android-base/unique_fd.h>
#include <linux/genetlink.h>
#include <netlink/genl/ctrl.h>
#include <netlink/genl/genl.h>
#include <utils/Looper.h>
#include <utils/Thread.h>

#include <chrono>
#include <condition_variable>
#include <future>
#include <list>
#include <mutex>
#include <set>
#include <string>
#include <thread>
#include <unordered_map>
#include <vector>

namespace aidl {
namespace android {
namespace hardware {
namespace thermal {
namespace implementation {

using ::android::base::boot_clock;
using ::android::base::unique_fd;
using WatcherCallback = std::function<std::chrono::milliseconds(
        const std::unordered_map<std::string, float> &uevent_sensor_map)>;

// A helper class for monitoring thermal files changes.
class ThermalWatcher : public ::android::Thread {
  public:
    explicit ThermalWatcher(const WatcherCallback &cb)
        : Thread(false), cb_(cb), looper_(new ::android::Looper(true)) {}
    ~ThermalWatcher() = default;

    // Disallow copy and assign.
    ThermalWatcher(const ThermalWatcher &) = delete;
    void operator=(const ThermalWatcher &) = delete;

    // Start the thread and return true if it succeeds.
    bool startWatchingDeviceFiles();
    // Give the file watcher a list of files to start watching. This helper
    // class will by default wait for modifications to the file with a looper.
    // This should be called before starting watcher thread.
    // For monitoring uevents.
    void registerFilesToWatch(const std::set<std::string> &sensors_to_watch);
    // For monitoring thermal genl events.
    void registerFilesToWatchNl(const std::set<std::string> &sensors_to_watch);
    // Wake up the looper thus the worker thread, immediately. This can be called
    // in any thread.
    void wake();

  private:
    // The work done by the watcher thread. This will use inotify to check for
    // modifications to the files to watch. If any modification is seen this
    // will callback the registered function with the new data read from the
    // modified file.
    bool threadLoop() override;

    // Parse uevent message
    void parseUevent(std::unordered_map<std::string, float> *sensor_map);

    // Parse thermal netlink message
    void parseGenlink(std::unordered_map<std::string, float> *sensor_map);

    // Maps watcher filer descriptor to watched file path.
    std::unordered_map<int, std::string> watch_to_file_path_map_;

    // The callback function. Called whenever thermal uevent is seen.
    // The function passed in should expect a string in the form (type).
    // Where type is the name of the thermal zone that trigger a uevent notification.
    // Callback will return thermal trigger status for next polling decision.
    const WatcherCallback cb_;

    ::android::sp<::android::Looper> looper_;

    // For uevent socket registration.
    ::android::base::unique_fd uevent_fd_;
    // For thermal genl socket registration.
    ::android::base::unique_fd thermal_genl_fd_;
    // Sensor list which monitor flag is enabled.
    std::set<std::string> monitored_sensors_;
    // Sleep interval voting result
    std::chrono::milliseconds sleep_ms_;
    // Timestamp for last thermal update
    boot_clock::time_point last_update_time_;
    // For thermal genl socket object.
    struct nl_sock *sk_thermal;
};

}  // namespace implementation
}  // namespace thermal
}  // namespace hardware
}  // namespace android
}  // namespace aidl
